PontiacBonnevilleClub.com

Ok, so instead of CTS-V I meant STS-V. It turns out from 2006 on up Cadillac started using the E67 ECM to run the Northstar. It's also used on a whole host of other vehicles and engines, fully compatible with OBD II, and costs $60. Pinouts are available, and it sounds like it wouldn't take much work at all to get a GXP running on one of these bad boys. I don't know if the gauges will work, but I'll cross that bridge when I get to it. It also has full support from hptuners, efilive, and other tuning software. It will need a TCM, which is also readily available for another $40. I think I'm on to something here...

Go for it.

But I will tell you, from having mine tuned, outside of mapping, there isn't a lot of options to play with.

I've been doing all kinds of research on this E67 and what the best donor vehicle is. The 2006 Buick Lucerne CXS is built on an updated H platform, so it is the most similar to a Bonneville. I want to find a totalled donor car so I can start comparing the engine harness and sensors. It looks very similar from the part diagrams I've seen. If I get it hooked up I'm willing to bet the engine will run without any tuning. That would most certainly pave the way for boosted applications. This is exciting.

Turbo GXP perhaps.... But where to fit the snail... Hmmm.

Rear mount... Lots of room in the rear axle well.

There's a company claiming to have modded and tuned a lucerne to 400hp, but no proof. I fully believe they modded it, but the hp gained is anyone's guess. I also read reports that a CAI actually hurts performance. MCM on youtube proved it on other cars, then last night I read someone with a Cadillac found the same results, but his testing was much less scientific. He did post the numbers to back it up.

The issue is that if you don't plumb the actual intake out of the engine bay (I.E. down through the hole in the stamped steel body piece behind the headlight, OR drill through the body below where the intake housing sits, in order to truly get fresh air, you end up sucking in more air, but it's hot air, straight off the radiator and the fans blowing it if they're on. This can lead to lean codes too. This was the issue I had on my first pass with my homemade concoction of a CAI. I ended up running it out and down behind the headlight (which was a very tight fit trying to fit a sleeved down 90* bend there), but I eventually got it to work. Plus where I sleeved it down in the bend area, sorta added a "venturi effect" adding a little cheap form of ram air. :p The other option I suppose would to be to fabricate a sheetmetal/plastic/other wall piece between the intake area and the radiator to help isolate it.

So yea, sucking in hot air isn't helping matters any.

I am starting a new thread to discuss upgrading to the E67 ECM. I've already started mapping the pins and so far 90% of everything matches up.

http://www.pontiacbonnevilleclub.com/fo ... 43702.html

nos4blood70 wrote:The GXP is an enjoy it as you find it kind of deal. Sure, you can make anything fast with money, however it'll still be a FWD understeery car with an archaic 4 speed.

I just have to say Carl, that my wife drives an SLE not unlike yours, and my GXP handles twice as good as the SLE.
If you have never driven one, you should, and if you have, it must have been a worn out POS to make you so negative on their handling.
I'm impressed with mine, and that is comparing it to my WS6 Trans Ams. You have to admit, the GXP is a huge improvement over lesser Bonnevilles.

Leon

Leon, Carl has been around many GXP's. Fact of the matter is, it's still wrong wheel drive and there is only sooo much that can be done to hide that fact. He's also been around and driven many high $$$ cars too... MB's, Lexus's, Bentley's, etc. There is a night and day difference.

I have never driven a lesser Bonneville, but I did own a 2002 Grand Prix GTP. The GXP feels much more solid and confident, especially now that I have new shocks in the back. It's a very nice car to drive, far more so than the grand prix at least.

CMNTMXR57 wrote:Leon, Carl has been around many GXP's. Fact of the matter is, it's still wrong wheel drive and there is only sooo much that can be done to hide that fact. He's also been around and driven many high $$$ cars too... MB's, Lexus's, Bentley's, etc. There is a night and day difference.

Apples to oranges!

I still believe that Pontiac achieved what they intended out of the Bonneville GXP.

And the "wrong wheel drive" line I keep seeing here is just lame, after all, this whole web site is based on the majority of the cars here being FWD cars. It makes it sound like only the privileged few have ever driven a RWD car, let alone know the differences between the two. Give us a little more credit than that.

I have driven both our Bonnevilles harder than most, and car for car, the GXP is head and shoulders above in the handling department over the SLE. THAT, is a fair comparison !

Leon

It may be "apples to oranges" BUT it is a valid comparison when he drives legitimate cars, some of which are known for their handling/performance prowess. Then he gets in a Bonneville...

Next time we're together, I'll toss you the keys to the Caddy, I'll even throw it in "competition driving mode", and let you have at it. You can let me know your thoughts afterwords.

The GXP > than other Bonneville's (which also handle pretty decently for FWD), and > than 99.9% of other FWD platformed vehicles. You can only put so many band-aids on to mask the inherent chassis dynamics of FWD.

And just so the peeps know, I tested the limits of the Stabilitrak system daily in mine...

Of course the GXP handles better, I should hope... Given solid sway bars, different tuned suspension and larger wheels. However, to quote Lane, if you think a Bonneville of any flavor handles well, then you have never driven anything that truly does handle well. I don't mean to be insulting, so please don't take it so, but that's the honest truth.

I don't think Pontiac achieved what they wanted out of the GXP either.. The model existed for 2 years and finally died. Is it a nice car? Yes. Definitely. I really like the way they look, and despite popular opinion I do believe that interior is much nicer than the lesser models. I would totally rock one as a daily if given the chance, but I just think it is a touch silly to call them sport sedans.

I look forward to seeing what can be accomplished with the tuning once it is opened up.

Tune, or not, I will still enjoy the GXP for what it is.
Some people are always going to be searching for something, and people like me can be perfectly happy with what is.

Thanks for the offer Lane, but I have driven LS Ram Air Trans Am and the new ZL1 Camaro,( are they "legitimate" enough?) to name a few, but to compare them to the Bonneville GXP would obviously be unfair.

Like I said, Pontiac finally had a FWD Bonneville that I was excited about since 1988 in the GXP model. I have no need nor want to mod this car, but I'm interested in seeing what can be done, and only then will I decide if that is a path I choose to follow.

I heard back from chrfab today and they're saying as far as torque is concerned, the factory 275hp cams are the best bet. They're claiming the best place to start is custom headers. The flex joint on stock exhaust has a very small diameter tube running through the center of it which severely inhibits flow. I've seen a picture of it and it's really bad. I haven't spent any time under the car to examine the feasibility of this, but it's a start. There's a lot of fab shops in this area, so i'll be calling around to see what it's gonna take. If I find someone who can do it for a reasonable price I will try to get several made so you guys can buy them. I also know a company that can ceramic coat them with a exceptionally high quality process that will never discolor.

From below it won't be hard to get to. Tight yes, but easily accessible if I recall.

Add another tuner company to the list supporting the GXP! I accidentally found these guys while researching different ECM options. http://www.pcmperformance.com/programming.html With three different options, I don't think it's necessary to pursue a different ECM anymore.

Madtuner just responded via email that he can't tune for cams done by chrfab, but that he can tune for them. I don't know why the exclusion. He also won't allow local or dyno tuning, so there goes my plan for September. Maybe this guy in New York will be more friendly.

Again, I wonder if it has something to do with the phasing of them. My guess is any aftermarket grind is going to be a complete package, meaning that the intake and exhaust cam are going to be synched with one another. That is probably where he will have a lot of trouble dialing them in.